1. Field of the Invention
The present invention relates to a process of preserving food and a food preservative. In particular, it relates to a process of preserving food with serine, which is one of amino acids, and a food preservative.
2. Related Art
Preservation of food for a long term without denaturation and putrefaction is very important from the viewpoint of economy, food hygiene and nutrition.
There are various causes for the denaturation or putrefaction of food, but the main one is proliferation of microorganism. Accordingly, to prevent the denaturation or putrefaction of food, prevention of microorganism growth, sterilization and elimination of microorganism are effective.
Prevention of microorganism growth in food is related to water activity, pH value, preservation temperature, atmosphere such as oxygen concentration, pressure and the like. Specifically, it may be carried out by dehydration, cold storage, freezing, salting, sugaring, pickling, smoking, use of an oxygen adsorber and the like. However, some of them cannot be applied depending on the kind of food.
Sterilization of microorganism includes a heat sterilization, a high pressure sterilization, a sterilization with radiation, electron beam and ultraviolet light, a microwave heat sterilization and use of an antimicrobial agent.
In the heat sterilization, microorganisms are completely perished by long-term heating at high temperature. However, the heating may possibly deteriorate taste and quality of food of some kinds. Further, short-term heating at low temperature cannot achieve satisfactory sterilization since highly heat-resistive microorganisms and spores are left.
With use of a direct sunbeam or a UV sterilization lamp, microorganisms on a food surface are perished. However, light hardly reaches the depth of food and oxidation of fatty acid happens easily.
Further, the antimicrobial agent often causes quite harmful effects not only to microorganisms but also to human bodies.
It has been known that glycine, which is one of amino acids, shows bacteriostasis to Escherichia coli in the presence of ethanol (see Food Hygienic Journal, Vol.40, No.4, p266-273). However, it has not been revealed yet that other amino acids show bacteriostasis.
Under the present circumstances, a sterilization process capable of preserving food easily and safely for a long time without deteriorating food quality has merely been selected from various sterilization processes, depending on the kinds of food.
The inventors of the present invention have conducted various examinations on an effective process of preserving food while minimizing the deterioration of food quality without any harm to human body. Then, they have found that addition of serine to food at a low temperature heating of food shows bacteriostasis to Gram-negative/positive bacilli generally contained in food. Thus, the present invention has been achieved.
According to the invention, provided is a process of preserving food comprising: adding serine to food.
Still according to the invention, provided is a food preservative comprising serine.